Knockdown from insecticide poisoning will be evaluated by assessing the function of the start-to-fly reflex response of the housefly. This reflex response involves interneuronal and motor neuronal elements whose response to poisoning may be followed during poisoning to determine any lesions at the cellular level. Toxicokinetics will be studied by measuring the concentration of carbofuran or permethrin in the hemolymph of house flies after topical application or injection. The nerve insensitivity resistance of Heliothis virescens will be monitored during the 1981 growing season in California.